JP3305517B2 - Method for producing colored aluminum alloy, aluminum alloy material, and aluminum alloy material having reddish milky white anodic oxide film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a colored aluminum alloy capable of obtaining a reddish milky white anodic oxide film by anodizing treatment and an aluminum alloy material having a reddish milky white anodic oxide film. .

[0002]

2. Description of the Related Art In general, an aluminum alloy plate used for a vessel, a container, a nameplate, a building material and the like is subjected to anodizing treatment from the viewpoint of corrosion resistance and the like. Also,
For these uses, a color-forming aluminum alloy that develops white to dark gray or silver by anodizing is often used.

Conventionally, as a technique for forming a milky white anodic oxide film, a proposal has been made to soak an aluminum alloy containing predetermined amounts of Fe and Ti and regulating the amount of Si at a temperature of 560 ° C. or higher (Japanese Patent Application Laid-Open No. 60-103197). ), Fe and Mg
Aluminum alloy containing a predetermined amount of
Proposal for soaking at a temperature of 60 ° C. or higher
No. 03197), and a proposal for soaking an aluminum alloy having specified amounts of Fe, Si and Cu at a temperature of 560 ° C. or higher (Japanese Patent Laid-Open No. 1-230755).

These are all techniques for obtaining a milky white anodic oxide film having a low color saturation. In recent years, aluminum alloy materials having a color tone in which a warm color such as a reddish or yellowish color is imparted to a milky white have been used in recent years. Requested. 2. Description of the Related Art Conventionally, as a technique for obtaining a milky color tone having a strong red tint (hereinafter, referred to as reddish milky white), there is a method of forming an anodized film and then dyeing the film.

[0005]

However, in the method of dyeing a film, when applied to, for example, aluminum products for kitchens such as pots, there is a problem that the dye is deteriorated and discolored when ignited. . Further, since a dyeing step is required after anodic oxidation, there is also a problem that the product cost increases.

The present invention has been made in view of the above-mentioned problems, and is directed to a colored aluminum alloy and an aluminum alloy capable of obtaining a reddish milky white anodic oxide film by anodizing treatment.
An object of the present invention is to provide a method for producing an aluminum alloy material having an aluminum alloy material and a reddish milky white anodic oxide film.

[0007]

The color-forming aluminum alloy according to the present invention is a film which exhibits a reddish milky white color by anodic oxidation.
A colored aluminum alloy for forming
e: 0.1 to 0.5% by weight, Cu: 0.05 to 0.
5% by weight, Mn: 0.5 to 1.5% by weight, Mg: 0.
1 to 0.8% by weight, Zn: 0.1 to 1.7% by weight and Ti: 0.005 to 0.04% by weight, the balance being Al and unavoidable impurities. Is 1.8 wt% or less, and the content ratio (Mn / Fe) of Mn and Fe is 2 or more. Also, the aluminum alloy according to the present invention
Material: Fe: 0.1 to 0.5% by weight, Cu: 0.05
To 0.5% by weight, Mn: 0.5 to 1.5% by weight, M
g: 0.1 to 0.8% by weight, Zn: 0.1 to 1.7
% By weight and Ti: 0.005 to 0.04% by weight
And the balance consists of Al and inevitable impurities,
And the total of the contents of Fe is 1.8% by weight or less,
Mn / Fe content ratio (Mn / Fe) is 2 or more
And a reddish milky white anodic oxide film is formed on the surface.
It is characterized by having been done.

The method for producing an aluminum alloy material having a reddish milky white anodic oxide film according to the present invention comprises the steps of:
To 0.5% by weight, Cu: 0.05 to 0.5% by weight,
Mn: 0.5 to 1.5% by weight, Mg: 0.1 to 0.1%.
8% by weight, Zn: 0.1 to 1.7% by weight, and Ti:
0.005 to 0.04% by weight, the balance being Al and unavoidable impurities, the total content of the Mn and the Fe being 1.8% by weight or less, the content of the Mn and the Fe Of an aluminum alloy having a ratio (Mn / Fe) of 2 or more at a temperature of 500 to 630 ° C. and 4 to 1
A step of homogenizing for 6 hours, a step of hot-rolling the ingot after homogenization at a starting temperature of 430 to 530 ° C., and a step of forming an anodic oxide film on the surface of the rolled aluminum alloy material And characterized in that:

[0009]

The reasons for adding the components and limiting the composition of the colored aluminum alloy according to the present invention will be described below.

[0010] Fe (iron): 0.1 to 0.5% by weight Fe has an effect of causing the anodic oxide film of the aluminum alloy to develop a milky white color. Fe combines with other elements in the aluminum alloy to form an Al-Fe eutectic compound. The Al-Fe eutectic compound, when present in the anodic oxide film, causes the anodic oxide film to develop a gray black to milky white color, and is also effective in refining recrystallized grains. In order to develop a milky white color, the Fe content is 0.1%.
It is necessary that the content be at least% by weight. If the Fe content exceeds 0.5% by weight, an AlFeMn-based giant intermetallic compound is generated, and the color tone sharply becomes blackish, and the processability when processing into a container or the like is deteriorated. . Therefore, the Fe content is set to 0.1 to 0.5% by weight.

Cu (copper): 0.05 to 0.5% by weight Cu has an effect of giving a yellow color to the color tone of the anodic oxide film. It is known that Al ₂ Cu is formed by adding Cu to an aluminum alloy, and this is anodized to give a yellow color to the color tone of the anodized film. By utilizing the action of Cu, a b ^* value described later can be adjusted to a range of +5 to +10. If the Cu content is less than 0.05% by weight, the anodic oxide film does not take on a yellow tint and the b ^* value does not become 5 or more. Cu
If the content exceeds 0.5% by weight, the corrosion resistance is reduced and the workability when processing into a vessel or the like is also reduced. Therefore, the Cu content is set to 0.05 to 0.5% by weight.

Mn (manganese): 0.5 to 1.5% by weight Mn has an effect of imparting a reddish color to the color of the anodic oxide film. That is, when the solid solution of AlMn is anodized, the color tone of the film becomes reddish. If the Mn content is less than 0.5% by weight, red color cannot be imparted to the anodic oxide film. On the other hand, if the Mn content exceeds 1.5% by weight, Al ₆ Mn precipitates and the color tone becomes blackish, and at the same time, an AlFeMn-based giant intermetallic compound is generated and the workability decreases. Therefore, the Mn content is set to 0.5 to 1.5% by weight.

Mg (magnesium): 0.1 to 0.8% by weight Mg is added to improve the strength of the aluminum alloy and ensure corrosion resistance. If the Mg content is less than 0.1% by weight, it is not possible to obtain the corrosion resistance and strength required for a vessel or the like. On the other hand, when the Mg content exceeds 0.8% by weight, the processability when processing into a vessel or the like is reduced. Therefore, the Mg content is set to 0.1 to 0.8% by weight.

Zn (zinc): 0.1 to 1.7% by weight Zn has an effect of giving a red color to the color tone of the anodic oxide film, and when added to an aluminum alloy,
Both a ^* value and b ^* value described later increase. If the Zn content is less than 0.1% by weight, the color tone of the oxide film does not take on a reddish tint, and if the Zn content exceeds 1.7% by weight, the processability when processing into a container or the like is reduced. For this reason, the Zn content is set to 0.1 to 1.7% by weight.

Ti (titanium): 0.005 to 0.04% by weight Ti acts as a grain refiner. By adding Ti to the aluminum alloy, the structure of the aluminum alloy ingot is refined, and it is possible to prevent rough surface when the aluminum alloy is processed into an object or the like. However, when the Ti content is 0.005
If the amount is less than the weight percentage, the effect of grain refinement is not sufficient. On the other hand, when the Ti content exceeds 0.04% by weight, a coarse compound is generated, and the surface state deteriorates. Therefore, the Ti content is set to 0.005 to 0.04% by weight.

It is known that the sum of the contents of Mn and Fe ≦ 1.8 Fe and Mn form a giant intermetallic compound with Al. When the sum of the Mn and Fe contents exceeds 1.8% by weight, a huge intermetallic compound is generated.
The upper limit of the total content of Mn and Fe is 1.8% by weight.

Mn / Fe content ratio: Mn / Fe ratio ≧ 2 The Mn / Fe content ratio is defined to stabilize the color tone. When the Mn / Fe ratio is 2 or more, the color of the anodic oxide film becomes milky white with a red tint. However, Mn
When the / Fe ratio is less than 2, an AlFeMn intermetallic compound is generated, and the color tone of the anodic oxide film becomes black. Therefore, the ratio of the contents of Mn and Fe needs to be 2 or more.

In the method of the present invention, the aluminum alloy having the above-mentioned composition is homogenized at a temperature of 500 to 630 ° C. for 4 to 16 hours, and then subjected to hot rolling at a starting temperature of 430 to 530 ° C. And anodizing treatment. Hereinafter, the reasons for limiting the conditions during the homogenization treatment and the hot rolling will be described.

Homogenization Treatment The aluminum alloy according to the present invention can obtain a milky white anodic oxide film by changing the form of Al-Fe crystallized material to Al ₃ Fe. If the homogenization treatment temperature (hereinafter referred to as soaking temperature) is less than 500 ° C., the form of the Al—Fe crystallized material does not shift from Al ₆ Fe to Al ₃ Fe, and the color tone of the anodic oxide film becomes black. It will take on. Also, when the homogenization processing time (hereinafter, referred to as soaking time) is less than 4 hours, the color tone becomes blackish similarly.

On the other hand, when the soaking temperature exceeds 630 ° C., M
Precipitation of n occurs, an AlFeMn-based giant intermetallic compound is generated, and the processability when processing into a vessel or the like is reduced, and the color tone of the anodic oxide film also becomes blackish. Similarly, when the soaking time exceeds 16 hours, the AlFe
A large Mn-based intermetallic compound is produced. Therefore, the homogenization treatment conditions are 4 to 16 at a temperature of 500 to 630 ° C.
Time.

[0021] By defining the hot rolling start temperature hot rolling start temperature to prevent the hot fibers, the resulting uniform surface state and color after the anodic oxidation. If the hot rolling start temperature is lower than 430 ° C., the deformation resistance increases, and hot rolling becomes difficult. Also, if the starting temperature is 5
When the temperature exceeds 30 ° C., hot fibers are generated and a uniform surface cannot be obtained. Therefore, the hot rolling start temperature is 4
30 to 530 ° C.

Anodized film thickness: 10 to 25 μm If the thickness of the anodized film is less than 10 μm, the anodized film does not develop a reddish milky white color due to the effect of the gloss of the substrate.
Further, when the thickness of the anodic oxide film exceeds 25 μm, the color tone of the anodic oxide film becomes blackish. For this reason, the thickness of the anodic oxide film is preferably set to 10 to 25 μm.

A ^* value: 0 to +2, b ^* value: +5 to +10 In order to make the color tone of the anodic oxide film good reddish milky white,
Define the a ^* and b ^* values. The a ^* value, b ^* value and L ^* value described later are cited in JIS Z8729 in the standard (CIE1976) recommended by the International Commission on Illumination in 1976. When the a ^* value is less than 0, the color tone becomes greenish, and when it exceeds +2, the color tone becomes reddish purple, and in any case, the warmth of the color tone unique to milky white disappears. If the b ^* value is less than +5, there is no warming of the color tone characteristic of milky white, and if it exceeds +10, the yellow color is too strong and the red color is lost. Therefore, the a ^* value is 0 to +2,
The b ^* value is +5 to +10.

As described above, the structure of the aluminum alloy is regulated, and the aluminum alloy is homogenized and hot-rolled under predetermined conditions, and then subjected to anodizing treatment to obtain a reddish milky white anodic oxide film. Can be produced. The anodic oxidation conditions are not particularly limited.
1 to 30% by weight using an electrolyte solution at a temperature of 10 to 40 ° C.
The anodic oxidation treatment may be performed under the condition of 000 seconds or more.

[0025]

EXAMPLES Examples of the present invention will be described below in comparison with comparative examples that depart from the scope of the claims.

First, the relationship between the composition of the aluminum alloy, the color tone and the mechanical properties was examined. That is, an aluminum alloy ingot having the composition shown in Table 1 below was produced. Next, these aluminum alloy ingots were homogenized at a temperature of 550 ° C. for 10 hours, and then hot-rolled at a starting temperature of 490 ° C. to obtain a rolled material having a thickness of 2 mm. Next, finish annealing was performed on the rolled material at a temperature of 340 ° C. for 2 hours to obtain a test material. This test material was anodized in sulfuric acid having a concentration of 15% by weight under the conditions of a current density of 2 A / dm ² and a temperature of 20 ° C. for 2000 seconds. Thereafter, the thickness of the anodized film, color tone after anodic oxidation, proof stress, and crystal grain size of this test material were measured. The results are summarized in Table 2 below.

The color tone was measured with a high-speed spectrophotometer. The L ^* value is a value indicating lightness, and the lightness is higher as the L ^* value is larger. In order to make it reddish milky white, the L ^* value is 65-65.
Preferably it is 80. In addition, a ^* is a value indicating the strength of reddish taste, + indicates that the reddish taste is strong, and-indicates that the greenish taste is strong. In order to obtain a reddish milky white color, the a ^* value is 0 to +
It needs to be 2. Further, b ^* is a value indicating the intensity of yellowish tint, + indicates that yellowish tint is strong, and-indicates that blue tint is strong. For reddish milky white, the b ^* value is +5
It needs to be +10.

The proof stress was evaluated by preparing a JIS No. 5 test piece and measuring the proof strength of the test piece. In order to use as pots and other utensils, it is necessary that the proof stress be 60 to 75 MPa.

The crystal grain size affects the surface properties when processed into a pot or other vessel. When the crystal grain size is 40 μm or more, roughening occurs when drawing is performed.

[0030]

[Table 1]

[0031]

[Table 2]

As is clear from Table 2, Examples 1 to
5 has an L ^* value of 68.8 to 79.1 and an a ^* value of +
0.7 to +1.7, b ^* value is +5.5 to +9.5, a reddish milky white anodic oxide film can be obtained, and the proof stress is 61 to 75 MPa and the crystal grain size is 22 to 27 µ.
m and mechanical properties suitable for application to utensils such as pans.

On the other hand, Comparative Examples 1 to 6, 9, and 10 in which the Fe content, Cu content, Mn content, Zn content and Ti content were outside the scope of the present invention, and the Mn / Fe ratio of the present invention Comparative Example 13 out of the claims was a
^{The *} value or b ^* value was out of the predetermined range, and a reddish milky white oxide film could not be obtained. Comparative Examples 7 and 8 in which the Mg content is out of the claims, Comparative Examples 11 and 12 in which the Ti content is out of the claims, and Mn + F
In Comparative Example 14 in which the total content of e was out of the scope of the claims of the present application, none of the mechanical properties were satisfactory.

Next, the relationship between the homogenization treatment and the hot rolling conditions and the color tone and mechanical properties was examined. That is, using an aluminum alloy having the same composition as that of Example 1 in Table 1, a homogenization treatment and hot rolling were performed under the conditions shown in Table 3 below. Then, test materials were formed in the same manner as in Examples 1 to 5 and Comparative Examples 1 to 14, and the proof stress, crystal grain size, thickness and color tone of the anodic oxide film were measured. The results are summarized in Table 4.

[0035]

[Table 3]

[0036]

[Table 4]

As is apparent from Table 4, Example 6,
No. 7 was able to obtain an anodic oxide film of a desired color tone. In addition, mechanical properties such as proof stress and crystal grain size were also good. On the other hand, Comparative Example 15 having a high soaking temperature and a high hot rolling start temperature and Comparative Example 1 having a high soaking temperature and a long soaking time.
6 had an L ^* value of less than 65. Comparative Example 17 in which the soaking temperature was low and the hot rolling start temperature was low was L ^*
The value was as large as 84.5, the a ^* value was -0.7, and the desired color tone could not be obtained.

[0038]

As described above, the colored aluminum alloy according to the present invention contains a predetermined amount of Fe, Cu, Mn, Mg, Zn and Ti, the total amount of Mn and Fe, and the Mn / Fe ratio. Was restricted to a certain range,
A reddish milky white anodic oxide film can be obtained. Also,
This aluminum alloy has mechanical properties suitable for objects such as pots, containers, nameplates, building materials, and the like.

On the other hand, in the method of the present invention, since the above-mentioned color-forming aluminum alloy is subjected to homogenization treatment and hot rolling under predetermined conditions and then subjected to anodic oxidation treatment, it has a reddish milky white anodic oxide film. An aluminum alloy material can be manufactured stably.

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Claims (4)

(57) [Claims] 1. A film showing a reddish milky white color by anodic oxidation
A colored aluminum alloy for forming
e: 0.1 to 0.5% by weight, Cu: 0.05 to 0.
5% by weight, Mn: 0.5 to 1.5% by weight, Mg: 0.
1 to 0.8% by weight, Zn: 0.1 to 1.7% by weight and Ti: 0.005 to 0.04% by weight, the balance being Al and unavoidable impurities. A total aluminum content of 1.8% by weight or less, and a ratio (Mn / Fe) of the content of Mn to the content of Fe of 2 or more. 2. Fe: 0.1 to 0.5% by weight, Cu:
0.05 to 0.5% by weight, Mn: 0.5 to 1.5 weight
%, Mg: 0.1 to 0.8% by weight, Zn: 0.1%
1.7 to 1.7% by weight and Ti: 0.005 to 0.04% by weight
%, The balance consisting of Al and unavoidable impurities,
The total content of the Mn and the Fe is 1.8% by weight or less.
Below, the content ratio of the Mn and the Fe (Mn / Fe)
Is 2 or more, and its surface is a reddish milky white anodic oxide film
Aluminum alloy characterized by the formation of
Wood. 3. Fe: 0.1 to 0.5% by weight, Cu:
0.05 to 0. 5 % by weight, Mn: 0.5 to 1.5% by weight, Mg: 0.1 to 0.8% by weight, Zn: 0.1 to 1.7% by weight, and Ti: 0.005 to 0.04% by weight %, The balance consisting of Al and unavoidable impurities,
The sum of the contents of Mn and Fe is 1.8% by weight or less, and the ratio of the contents of Mn and Fe (Mn / Fe)
A homogenizing treatment of an ingot of an aluminum alloy having a value of 2 or more at a temperature of 500 to 630 ° C. for 4 to 16 hours, and starting the ingot after the homogenizing treatment at a temperature of 430 to 530.
A method for producing an aluminum alloy material having a reddish milky white anodic oxide film, comprising: a step of hot rolling at a temperature of 0 ° C .; and a step of forming an anodic oxide film on the surface of the aluminum alloy material after rolling. . 4. The thickness of the anodic oxide film is 10 to 25.
μm, a ^* value indicating the intensity of reddish taste (JIS Z872
9) is 0 to +2, b ^* value indicating the intensity of yellow tint (JIS
The method for producing an aluminum alloy material having a reddish milky white anodic oxide film according to claim 3 , wherein Z8729) is from +5 to +10.